A railway freight wagon that is employed for transporting a shipping container conventionally is constructed to accommodate at least one container wholly within a well of the wagon. Also, such a wagon typically is constructed with its opposite ends formed with raised platforms below which wheel assemblies are located. In order that an extended container or a plurality of shorter containers may be accommodated within the overall length of the wagon, including in the portions of the length that are occupied by the end platforms, retractable support mechanisms are provided within opposite side walls of the wagon for supporting the container(s) at an elevated position (i.e., at the level of the end platforms) within the wagon well. The support mechanisms are positioned at spaced intervals along the length of the side walls of the wagon and they are arranged to be retracted into the side walls of the wagon to facilitate flexible use of the wagon. Thus, the support mechanisms when retracted permit the nesting of a container wholly within the wagon well and when extended permit accommodation of one or more containers at the level of the end platforms.
Each support mechanism conventionally comprises a support arm that is mounted to a vertically extending axle for swinging movement horizontally into and out from the side wall of the wagon. Having regard to the loads that typically are to be carried by the support mechanism and bending moments imposed on the vertically extending axle, the support mechanism must be constructed in a size that occupies a large stowage space (this being a problem when the overall width of a wagon is critical). Horizontal swinging of the support arm into and out from a container supporting position has been found to be inconvenient.
SUMMARY OF THE PRESENT INVENTION
Broadly defined, the present invention provides a support mechanism for mounting in a side wall of a railway freight wagon and for supporting a shipping container on the wagon when the support mechanism is deployed for use. The support structure has a frame structure, arranged to be mounted in a side wall of the wagon, and at least one support arm pivotally mounted on the frame structure for movement about a substantially horizontal axis, the support arm being arranged to pivot between a first position in which it is stowed at least in part within the frame structure and a second position in which it extends away from the frame structure in a substantially horizontal direction so it is deployed to support a shipping container.
The frame structure may be one having spaced sidewalls between which an axle extends at a lower region and the support arm is pivotally mounted on the axle and is disposed between the sidewalls for pivotal movement. The structure can be such that simple manual action is all that is required to move the support arm between its positions.
The support arm when located in the first position may optionally be stowed in any way that that permits the positioning of a container within the wagon at a level below that of the support mechanism, without interference from the support arm. However, the support arm desirably is configured and/or arranged to extend in a generally vertical direction and to locate substantially entirely within the frame structure when stowed in the first position.
Various structural arrangements may optionally be provided for determining the limit of pivotal movement of the support arm when it is in the second position, but in one embodiment of the invention the support arm is formed integrally with an abutment face that is arranged and positioned to engage with a portion of the frame structure when the support arm is located in the second position. Thus, engagement between the abutment face of the support arm and the frame structure provides for referral from the support arm to the frame structure and thence to the wall of the wagon of a force exerted on the support arm by a container carried by the support arm.
A locking mechanism may optionally be employed to lock the support arm in the first and/or second position, to prevent inadvertent pivotal movement of the support arm when it is not supporting a container within a wagon. In one embodiment of the invention such locking mechanism comprises a retractable latching mechanism that is employed to latch the support arm in the first position and, desirably, to latch the support arm when in each of the first and the second positions. Such latching mechanism may comprise a spring-loaded plunger that is engaged in respective ones of two recesses in the support arm when the support arm is alternatively in the first and second positions.
Two of the support mechanisms as above described and defined may be positioned side-by-side within a single frame structure with a dividing frame member located between the two mechanisms. Such support mechanism is hereinafter referred to as a dual support mechanism.
The present invention further subsists in a railway freight wagon which is arranged to carry at least one shipping container and a plurality of support mechanisms located within side walls of the wagon. Each support mechanism comprises a frame structure located within a side wall portion of the wagon, and at least one support arm pivotally mounted to in the frame structure. The support arm is pivotal between a first position in which it is stowed at least in part within the frame structure and a second position in which it extends outwardly or away from the frame structure in a substantially horizontal direction for engagement by a container when positioned within the wagon, whereby the support arm contributes to supporting the container.
The invention will be more fully understood from the following description of an illustrative embodiment of a support mechanism and a freight wagon in which a plurality of the support mechanisms is located. The description is provided with reference to the accompanying drawings.